Centre for Environmental Sciences, Environmental Biology, Hasselt University, Diepenbeek, Belgium.
J Plant Physiol. 2011 Mar 1;168(4):309-16. doi: 10.1016/j.jplph.2010.07.010. Epub 2010 Sep 15.
The cellular redox state is an important determinant of metal phytotoxicity. In this study we investigated the influence of cadmium (Cd) and copper (Cu) stress on the cellular redox balance in relation to oxidative signalling and damage in Arabidopsis thaliana. Both metals were easily taken up by the roots, but the translocation to the aboveground parts was restricted to Cd stress. In the roots, Cu directly induced an oxidative burst, whereas enzymatic ROS (reactive oxygen species) production via NADPH oxidases seems important in oxidative stress caused by Cd. Furthermore, in the roots, the glutathione metabolism plays a crucial role in controlling the gene regulation of the antioxidative defence mechanism under Cd stress. Metal-specific alterations were also noticed with regard to the microRNA regulation of CuZnSOD gene expression in both roots and leaves. The appearance of lipid peroxidation is dual: it can be an indication of oxidative damage as well as an indication of oxidative signalling as lipoxygenases are induced after metal exposure and are initial enzymes in oxylipin biosynthesis. In conclusion, the metal-induced cellular redox imbalance is strongly dependent on the chemical properties of the metal and the plant organ considered. The stress intensity determines its involvement in downstream responses in relation to oxidative damage or signalling.
细胞氧化还原状态是金属植物毒性的一个重要决定因素。在这项研究中，我们研究了镉（Cd）和铜（Cu）胁迫对拟南芥细胞氧化还原平衡的影响，以及与氧化信号和损伤的关系。这两种金属都很容易被根部吸收，但向地上部分的转运仅限于 Cd 胁迫。在根部，Cu 直接诱导氧化爆发，而 NADPH 氧化酶介导的酶促 ROS（活性氧）产生似乎在 Cd 引起的氧化应激中很重要。此外，在根部，谷胱甘肽代谢在控制 Cd 胁迫下抗氧化防御机制的基因调控中起着关键作用。在根和叶中，CuZnSOD 基因表达的 miRNA 调节也表现出金属特异性的改变。脂质过氧化的出现是双重的：它既可以作为氧化损伤的指标，也可以作为氧化信号的指标，因为金属暴露后会诱导脂氧合酶，而脂氧合酶是类二十烷酸生物合成的初始酶。总之，金属诱导的细胞氧化还原失衡强烈依赖于金属的化学性质和所考虑的植物器官。胁迫强度决定了它在与氧化损伤或信号有关的下游反应中的参与程度。
